You know, when I first got Zaeed, I was pretty disappointed. He doesn't have normal conversation trees, after all. I warmed up to him in three stages.
1. In combat he's a merciless killing machine bad-ass who takes no shit from anyone. And he can have Squad Disruptor Ammo, making him a staple for any geth mission, especially on Insanity.
That's enough to use him.
2. He talks a lot for someone without normal conversation trees. Repeatedly examine anything in his room and you can get a long story about any of it. It's great. More, he always has something unique to say after most missions, which is awesome.
That's enough to actually like him.
3. He has mission-specific dialogue everywhere. From Garrus's recruitment mission (meet the Blue Sun leader) to Samara's, all over the place. He's chatty, witty, and crazier than a shithouse monkey.
He's still a reprehensible lunatic, but I've grown to really like him over time.
